I have an image taken in October 2010 of the same formation, from a point to the left of your image. In mine the mound would appear to be nearly twice the height as in yours. Any idea what year yours was taken?

UPDATE:
I found an image I took in August 2003 from nearly the same vantage as your image, and the height of the formation looks to be very similar to your image.

Thanks Art and Jim.
This was taken 15+ years ago.
I took another photograph at the same time that included a person for scale. The post is Mammoth #5 in this series. It dropped quickly to page two, so you may have missed it.
Charlie